How Pros Cut Molding Inside Corners

Dirt Farmer Jay here from DirtFarmerJay.com. If you're ever installing either crown molding or baseboard molding and it's going into a 90 degree corner and you want to make it right, there's a tip the pros use. Stay tuned and I'll show you what it is. All right, let's go ahead and begin with baseboard. This is four inch baseboard, but the technique I'm going to show you works whether it's a shorter profile, a taller profile, or a split profile. Now, one of the ways you can install in an inside corner baseboard like this is just a straight miter. And as you can see, I've cut a 45 degree on this and I've cut a 45 degree on this. Will it work? Yeah, most of the time, but it's not the preferred way to do it. If you join these two together and you put it together and it's truly a 90 degree corner, you're going to get a tight joint. But here's the problem. Most walls are not 90 degrees. They're either wider or smaller. So if it is less than 90 degrees, it's going to gap at the backside of the miter. If it's wider, then look what's happened. It's ugly. And so what you end up doing is filling this with caulk. Well, there's a method that carpenters have devised over the centuries to address this. It's called coping. That's really what it's called. C-O-P-I-N-G, coping. And what we're going to do is actually cut this section out. If you notice, the shape when you cut a 45 degree is exactly the same shape as the face of the joining molding. So if we cut that all away, what that's going to allow us to do is only have the joint touch at the front edge. And even if there is some variance this way, the gap will still be tight. So let me show you how we cope them. Okay, the first thing you're going to need is a coping saw. You've seen these kind of saws before at the hardware store. And this loop or this bow around here really allows you to get in far into a cut. But if you look close at the teeth, the teeth are set in a way I put them so they're going forward like a standard saw. And they will cut on the push stroke. All right, let's go to work here. Notice that we've cut this piece of molding at a 45. And when you do so, the front shape of the adjacent piece is revealed right along here. So what we're going to do is we're going to cut right along this profile. But we're going to cut back at about a 45 degree angle that's called an undercut that will allow an adjacent piece of molding when it's installed on the wall to just kiss right on the front edge. Therefore, if the angle is a little wide, a little narrow, it's still going to fit very well. This will take a little bit of practice. After a couple cuts, you'll get it and you'll find that your precision will kick up. So first thing we'll do is we're going to get cutting here. All right, we did a partial cut because that allows us to get another start. As you can see, that's pretty doggone close. Let's go ahead and get our second part of the cut going. Now notice right on this cut, I know of some skilled tradespeople that actually use their miter saw and cut this straight portion and then cut this profile portion to match it. But we're just going to go ahead and go straight across. All right, so notice that this is undercut a little bit. If you look at from this side, you can see the profile nicely. If you look from this side, you can see that I have back cut the molding. That's so that only this front edge is standing proud. So when you went to go use this, let's call that one wall, you would nail that molding onto the wall. This adjacent piece would come up to it. And notice, while it's not absolutely perfect, it's certainly within range. And with a little adjustment, you can either back file or sand. But notice one of the big benefits. If I pivot slightly in and out, the joint is still tight. It doesn't gap. And even just a little bit of caulk and paint in this corner will be beautiful. Well, that's how it's done for baseboard. Does it also work for crown molding? Absolutely. The same theory is used. And let me just show you a sample of that briefly. All right, so you'll have to use your imagination just a little bit here. But imagine that this is the wall and what I'm standing above the ceiling. And so this is attached to the wall at an angle like this. This next piece on an adjacent wall is coming along. Notice it's been coped and back cut. But we're going to roll it and we would place it up and then bring it into place. And as you can see, it's pretty doggone close. And this allows this side to be nailed all the way into the corner without both of them coming out and having a gap behind it. It's a superior way to do it. It's professional and it'll last a long time. Hey, it'll take you a little bit of practice and a little bit of noodling until it becomes muscle memory. But believe me, the results are well worth it. Hey, if you found this to be helpful, won't you like it? And better yet, subscribe to our channel. Until the next time, this is Dirt Farmer Jay from DirtFarmerJay.com.